Generally, a watch including a hand shaft display portion for indicating time analogously by hand positions and a liquid crystal display portion for indicating time digitally due to an electro-optic effect is known as a multiple display watch.
As an example of a multiple display watch of this type, disclosed by the present inventors in Japanese Patent Publication No. 16389/1987 is an illuminated multiple display watch equipped with a miniature lamp for illuminating a time display so that the current time can be viewed under dark conditions such as at night or the like.
With such an illuminated multiple display watch, however, there are difficulties in uniformly illuminating an entire display. Therefore, an improvement in such difficulties has been needed.
On the other hand, the progress in the technology for illumination using an electroluminescent (hereinafter abbreviated as "EL") element has allowed development of EL illuminated display watches using an EL element.
Conventionally, such EL illuminated display watches (1) as disclosed in Japanese Utility Models Laid-open No. 188633/1988, No. 45883/1989, and No. 80197/1994 are known.
Also, the EL illuminated display watches conventionally used include watches (2) of the types disclosed in Japanese Utility Models Laid-open No. 18986/1994 and No. 294668/1995.
In these watches, each whole time display can be uniformly illuminated.
However, the former (display watches (1)) aims at an EL illuminated display watch equipped with a digital display, whereas the latter (display watches (2)) aims at an EL illuminated display watch equipped with an analog display.
Because of this, it has been desired to realize a combination display timepiece equipped with EL illumination which is equipped with both an analog display and a digital display to be illuminated.
The watches shown in FIGS. 7 and 8 satisfy such a demand.
First, the combination display timepiece equipped with EL illumination shown in FIG. 7 will be illustrated with reference to the drawing.
FIG. 7 is a sectional view showing the major portion of an internal mechanism (module) of a conventional combination display timepiece equipped with EL illumination, in which the casing for the watch, the inside of the movement, and the like are omitted.
In FIG. 7, the symbol 11 represents a hand shaft display portion for indicating time analogously, including hands 12 representing a long hour hand and a short minute hand and a hand shaft 13 as a driving shaft for the hands 12. The hands 12 are rotated by driving the movement 14 to indicate the time. The movement 14 consists of a step motor, a reduction train wheel, and the like, though these are not shown. By these measures, the driving force of the step motor is transferred to the hands 12 via the hand shaft 13.
The symbol 15 represents a liquid crystal display portion for indicating time digitally, including two glass substrates 16, 17 which are stacked in the vertical direction (axial direction of the hand shaft 13) and a liquid crystal (not shown) sealed between the glass substrates 16, 17. The time is displayed by the electro-optic effect of the liquid crystal, which is controlled by the voltage to be applied. A twisted nematic (hereinafter abbreviated as "TN") liquid crystal is used as the liquid crystal. A deflecting plate is used in this TN liquid crystal, though it is not shown.
The symbol 18 represents a liquid crystal display portion support frame for supporting the liquid crystal display portion 15. The liquid crystal display portion support frame 18 is disposed on a circuit substrate 19. An electroconductive rubber 20 is pressure-welded on the circuit substrate 19 by this support frame 18 via the upper glass substrate 16. The liquid crystal display portion support frame 18 includes a first penetration window 18a facing the liquid crystal display portion 15 and a second penetration window 18b into which the hand shaft 13 is inserted and facing the movement 14. On the circuit substrate 19, an IC, a crystal vibrator, a pressure-up circuit, and the like are mounted. The electroconductive rubber 20 is compressed in the direction parallel to the each axis of the penetration windows 18a, 18b. The two terminals of the electroconductive rubber 20 are electrically connected to an electrode output portion 16a and an electrode 19a of the circuit substrate 19 respectively.
The symbol 21 represents an EL film for illuminating the liquid crystal display portion 15 from below. The EL film 21 is disposed between the lower glass substrate 17 and the circuit substrate 19 and is electrically connected to the circuit substrate 19 through a pressure coil spring 22. The EL film 21 is turned on and off by a switch (hereinafter abbreviated as "SW"), though not shown.
The symbol 23 represents a dial constituting a part of the hand shaft display portion 11. The dial 23 is disposed between the hands 12 and the liquid crystal display portion support frame 18. The dial 23 is provided with a shaft through hole 23a, into which the hand shaft 13 is inserted and a insertion hole 23b which faces the liquid crystal display portion 15. The liquid crystal display portion 15 can be viewed from above through the penetration window 23b of the dial 23 and the first penetration window 18a of the liquid crystal display portion support frame 18. Also, the dial 23 shields the electroconductive rubber 20 so that the electroconductive rubber 20 cannot be viewed from above (hand side).
In a combination display timepiece equipped with EL illuminationes formed in the above manner, the movement 14 is driven by a signal from a source transmitter and the driving force is transferred to the hands 12 through the hand shaft 13, thereby indicating the time analogously. In the same way, a voltage is applied to the liquid crystal display portion 15 from the circuit substrate 19 through the electroconductive rubber 20 by a signal from a source transmitter, thereby indicating the time digitally.
By these measures, the hand shaft display portion 11 and the liquid crystal display portion 15 can be viewed to determine the time in general under the condition where the EL film is turned off. Also, even in the case of a dark condition such as at night or the like, the liquid crystal display portion 15 can be viewed to determine the time under the condition where the EL film 21 is turned on by the SW (not shown).
Next, the combination display timepiece equipped with EL illumination shown in FIG. 8 will be illustrated with reference to the drawing.
FIG. 8 is a sectional view showing the major portion of an internal mechanism (module) of a conventional combination display timepiece equipped with EL illumination, in which the parts other than a full liquid crystal display portion, a liquid crystal display portion support frame, an El element, and a dial are represented by the same symbols as in FIG. 7, therefore detailed descriptions are omitted. Also, in FIG. 8, the casing for the watch, the inside of the casing, and the like are omitted.
In FIG. 8, the symbol 35 represents a full liquid crystal display portion for indicating time digitally, including two glass substrates 36, 37 which are stacked in the vertical direction arid a liquid crystal (not shown) sealed between the glass substrates 36, 37. The time is displayed by the electro-optic effect of the liquid crystal, which is controlled by the voltage applied. As the liquid crystal, a TN liquid crystal is used in the same way as in FIG. 7. In this TN liquid crystal, a deflecting plate is used generally, though it is omitted in the same way as in FIG. 7. The full liquid crystal display portion 35 is formed of a display of a plane shape such as a square shape, an octagonal shape, or the like. Also, a shaft insertion hole 35a for inserting a hand shaft 13 is provided in the center of the liquid crystal display portion 35.
The symbol 38 represents a liquid crystal display portion support frame for supporting the full liquid crystal display portion 35. The liquid crystal display portion support frame 38 is disposed on a circuit substrate 19. An electroconductive rubber 20 is pressure-welded on the circuit substrate 19 by this support frame 38 via the upper glass substrate 36. In the center of the liquid crystal display portion support frame 38, a penetration window 38a is provided into which the hand shaft 13 is inserted and which faces the full liquid crystal display portion 35. The electroconductive rubber 20 is compressed in the direction parallel to the axis of the penetration window 38a. The two terminals of the electroconductive rubber 20 are electrically connected to an electrode output portion 36a of the upper glass substrate 36 and an electrode 19a of the circuit substrate 19 respectively.
The symbol 41 represents an EL film for illuminating the entire liquid crystal display portion 35 from below (opposite to the hand side). The EL film 41 is disposed between the lower glass substrate 37 and the movement 14 and electrically connected to the circuit substrate 19 through a pressure coil spring 22. The EL film 41 is formed of a film with almost the same plane shape as that of the full liquid crystal display portion 35 and which is turned on and off by an SW, though not shown. In the center of the EL film 41, a shaft through-hole 41a for inserting the hand shaft 13 is provided.
The symbol 43 represents a dial constituting a part of a hand shaft display portion 11. The dial 43 has a penetration window 43a which faces the full liquid crystal display portion 35 and is disposed around the hand 12. The liquid crystal display portion 35 and the hand 12 can be viewed from above through the penetration window 43b of the dial 43. Also, the dial 43 shields the electroconductive rubber 20 so that the electroconductive rubber 20 cannot be viewed from above (hand side).
In the combination display timepiece equipped with EL illumination formed in the above manner, the movement 14 is driven by a signal from a source transmitter and the driving force is transferred to the hand 12 through the hand shaft 13, thereby indicating the time analogously. A voltage is applied to the full liquid display 35 from the circuit substrate 19 through the electroconductive rubber 20 by a signal from a source transmitter, thereby indicating the time digitally in the same manner as in the combination display timepiece equipped with EL illumination shown in FIG. 7.
By these measures, the hand shaft display portion 11 and the liquid crystal display portion 35 can be viewed to determine the time in general under the condition where the EL film 41 is turned off. Also, even in the case of dark conditions such as at night or the like, the liquid crystal display portion 35 can be viewed to determine the time by either illuminating light or leak light obtained by turning on the EL film 41.
In the combination d splay timepiece equipped with EL illumination shown in FIG. 7, the liquid crystal display portion 15 can be viewed to determine the time, because the liquid crystal display portion is illuminated with light obtained by turning on the EL film 21. However, because this multiple display has a structure in which the liquid crystal display portion support frame 18 is interspaced between the hand 12 and the EL film 21, the light irradiated from the EL film 21 is cut by the liquid crystal display portion support frame 18 so that the light never reaches the hand 12. Hence, under dark conditions such as at night or the like, the time cannot be determined by the hand 12.
On the other hand, in the combination display timepiece equipped with EL illumination shown in FIG. 8, the full liquid crystal display portion 35 can be viewed to determine the time by the illuminating light obtained by turning on the EL film 41. Also, the full liquid crystal display portion 35 can be viewed to determine the time by the leaked light obtained by turning on the EL film 41. However, in the system adopting the full liquid crystal display portion 35, it is necessary to manufacture the shaft insertion hole 35a in the glass liquid crystal cell (full liquid crystal display portion 35) by mechanical processing, causing the processing cost to be high.
Also, the mechanical processing of the shaft insertion hole 35a causes a reduction in mechanical strength so that the impact resistance of the entire watch is impaired. As a result, a specific impact resistant structure is required, which causes high manufacturing costs.
Further, a wrist watch produced from the combination display timepiece equipped with EL illumination of the type using the full liquid crystal display portion 35 has the drawback that the illumination on an entire display is darkened because the full liquid crystal display portion 35 is covered with a deflecting plate. In addition, as the area occupied by the liquid crystal display portion of a watch increases, the configuration of the watch much resembles that of a watch of the type with digital display using a liquid crystal and hence the watch of the type using the liquid crystal display portion is lower in product value than the analog watch of the type using the hands for display.
As is clear from the above descriptions, in the conventional combination display timepiece equipped with EL illuminationes, the liquid crystal display portion 15 is illuminated by light emitted from the EL film 21 which is turned on. However, the hand shaft display portion 11 is never illuminated and hence the time is never determined by the analog display under dark conditions such as at night or the like. Also, though the full liquid crystal display portion 35 is illuminated by light emitted from the EL film 41 which is turned on, the hand shaft display portion 11 is only illuminated by its leaked light so that the hand shaft display portion 11 can be viewed sometimes only with difficulty under dark conditions such as at night or the like.
Also, for a watch of the type using the full liquid crystal display portion 35, the manufacturing and processing cost is high and the product value is reduced.
Accordingly, the present invention has been achieved in view of this situation and has an object of providing a combination display timepiece equipped with EL illumination comprising disposing an EL element for illuminating a hand shaft display portion and a liquid crystal display portion through a light transmission part of a liquid crystal display portion support frame at a position opposite a hand shaft display portion on a liquid crystal display portion support frame, the EL element being supported by the liquid crystal support frame at a position eccentric from the driving axis of a hand, with the time indicated by an analog display and a digital display under dark conditions such as at night or the like, attaining a reduction in the manufacturing and processing costs, and promoting the product value.